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Agreement between activPAL and ActiGraph for assessing children's sedentary time

Ridgers, Nicola D., Salmon, Jo, Ridley, Kate, O'Connell, Eoin, Arundell, Lauren and Timperio, Anna 2012, Agreement between activPAL and ActiGraph for assessing children's sedentary time, International journal of behavioural nutrition and physical activity, vol. 9, no. 15, pp. 1-18, doi: 10.1186/1479-5868-9-15.

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Title Agreement between activPAL and ActiGraph for assessing children's sedentary time
Author(s) Ridgers, Nicola D.ORCID iD for Ridgers, Nicola D.
Salmon, JoORCID iD for Salmon, Jo
Ridley, Kate
O'Connell, Eoin
Arundell, LaurenORCID iD for Arundell, Lauren
Timperio, AnnaORCID iD for Timperio, Anna
Journal name International journal of behavioural nutrition and physical activity
Volume number 9
Issue number 15
Start page 1
End page 18
Total pages 18
Publisher BioMed Central
Place of publication London, U. K.
Publication date 2012-02
ISSN 1479-5868
Keyword(s) accelerometry
objective assessment
sedentary time
sedentary behavior
Summary Background
Accelerometers have been used to determine the amount of time that children spend sedentary. However, as time spent sitting may be detrimental to health, research is needed to examine whether accelerometer sedentary cut-points reflect the amount of time children spend sitting. The aim of this study was to: a) examine agreement between ActiGraph (AG) cut-points for sedentary time and objectively-assessed periods of free-living sitting and sitting plus standing time using the activPAL (aP); and b) identify cut-points to determine time spent sitting and sitting plus standing.

Forty-eight children (54% boys) aged 8–12 years wore a waist-mounted AG and thigh-mounted aP for two consecutive school days (9–3:30 pm). AG data were analyzed using 17 cut-points between 50–850 counts·min−1 in 50 counts·min−1 increments to determine sedentary time during class-time, break time and school hours. Sitting and sitting plus standing time were obtained from the aP for these periods. Limits of agreement were computed to evaluate bias between AG50 to AG850 sedentary time and sitting and sitting plus standing time. Receiver Operator Characteristic (ROC) analyses identified AG cutpoints that maximized sensitivity and specificity for sitting and sitting plus standing time.

The smallest mean bias between aP sitting time and AG sedentary time was AG150 for class time (3.8 minutes), AG50 for break time (−0.8 minutes), and AG100 for school hours (−5.2 minutes). For sitting plus standing time, the smallest bias was observed for AG850. ROC analyses revealed an optimal cut-point of 96 counts·min−1 (AUC = 0.75) for sitting time, which had acceptable sensitivity (71.7%) and specificity (67.8%). No optimal cut-point was obtained for sitting plus standing (AUC = 0.51).

Estimates of free-living sitting time in children during school hours can be obtained using an AG cut-point of 100 counts·min−1. Higher sedentary cut-points may capture both sitting and standing time.
Notes This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Language eng
DOI 10.1186/1479-5868-9-15
Field of Research 110699 Human Movement and Sports Science not elsewhere classified
Socio Economic Objective 920499 Public Health (excl. Specific Population Health) not elsewhere classified
HERDC Research category C1 Refereed article in a scholarly journal
ERA Research output type C Journal article
Grant ID NHMRC 533815
NHMRC 1026216
Copyright notice ©2012, Ridgers et al.
Free to Read? Yes
Use Rights Creative Commons Attribution licence
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Document type: Journal Article
Collection: Centre for Physical Activity and Nutrition Research
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Created: Tue, 28 Feb 2012, 12:21:30 EST by Jane Moschetti

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